The objective of the present work is to determine the operating conditions of an activated carbon filter, based on the characteristics of breakthrough curves. For this we apply the technical developed by Mickaels [1] for the ionic exchange and applied by Luchkis [2] for the adsorption, and which is the mass transfer zone. To reach our goal, an evaluation of the operating conditions (height of the bed, flow and concentration of effluent) on the characteristics of the mass transfer zone was made and an explanation of the mechanism of adsorption was given. Thereafter a modeling of the experimental results was done. (c) 2006 Elsevier B.V. All rights reserved.